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vb.net字符补位 vb format 补0
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vb.net 实现ComboBox输入字符自动补充字符
Public Sub AutoComplete(ByVal cmb As ComboBox, ByVal e As System.Windows.Forms.KeyPressEventArgs)
If cmb.DataSource Is Nothing Then
Return
End If
If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Enter) Then
Return
End If
Dim strFindStr As String = ""
If e.KeyChar = Microsoft.VisualBasic.ChrW(Keys.Back) Then
If (cmb.SelectionStart = cmb.Text.Length) Then
If cmb.Text.Length 0 Then
strFindStr = cmb.Text.Substring(0, cmb.Text.Length - 1)
End If
Else
If cmb.SelectionStart 0 Then
strFindStr = cmb.Text.Substring(0, cmb.SelectionStart - 1)
End If
End If
e.Handled = False
Else
If (cmb.SelectionLength = 0) Then
strFindStr = cmb.Text + e.KeyChar
Else
If (cmb.SelectionStart = cmb.Text.Length) Then
strFindStr = e.KeyChar
Else
If cmb.SelectionStart 0 Then
strFindStr = cmb.Text.Substring(0, cmb.SelectionStart - 1) + e.KeyChar
Else
strFindStr = e.KeyChar
End If
End If
End If
End If
Dim intIdx As Integer = -1
Dim dv As DataView
If TypeOf (cmb.DataSource) Is DataTable Then
dv = CType(cmb.DataSource, DataTable).DefaultView
If strFindStr "" Then
dv.RowFilter = cmb.DisplayMember " Like '%" strFindStr "%'"
Else
dv.RowFilter = ""
End If
cmb.DataSource = dv
cmb.SelectedIndex = -1
cmb.Text = strFindStr
Else
dv = CType(cmb.DataSource, DataView)
If strFindStr "" Then
dv.RowFilter = cmb.DisplayMember " Like '%" strFindStr "%'"
Else
dv.RowFilter = ""
End If
cmb.DataSource = dv
cmb.SelectedIndex = -1
cmb.Text = strFindStr
End If
cmb.SelectionStart = strFindStr.Length
e.Handled = True
End Sub
Private Sub comboBox1_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles comboBox1.KeyPress
AutoComplete(sender, e)
End Sub
相关问答
Q1: VB.net 字符转换问题 字符（汉字、数字、字母、符号）>gb2312>unicode>utf8， 以及逆转的方法
字符编码转换吗?
1.字符与gb2312(gbk的子集)：
Public Function GBKEncode(ByVal sInput As String) As String
Dim ret_GBKEncode As String = ""
Dim i As Integer
Dim startIndex As Integer = 0
Dim endIndex As Integer
Dim x() As Byte = System.Text.Encoding.Default.GetBytes(sInput) '字符以及字符串在vb2008中都是以unicode编码存储的
endIndex = x.Length - 1
For i = startIndex To endIndex
ret_GBKEncode = "%" Hex(x(i))
Next
Return ret_GBKEncode
End Function
'GBK解码
Public Function GBKDecode(ByVal sInput As String) As String
sInput = sInput.Replace("%", "")
Dim ret_GBKDecode As String = ""
Dim sLen As Integer = sInput.Length
Dim n As Integer = sLen \ 2
Dim sBytes(0 To n - 1) As Byte
'转化为字节码
For i As Integer = 1 To n
sBytes(i - 1) = CByte("H" sInput.Substring(2 * i - 2, 2))
Next
'将字节码转化为字符串
ret_GBKDecode = System.Text.Encoding.Default.GetString(sBytes)
Return ret_GBKDecode
End Function
2.Unicode字符串为UTF-8
Imports System.Text
Public Function StringAsUtf8Bytes(ByVal strData As String) As Byte()
Dim bytes() As Byte
bytes = Encoding.UTF8.GetBytes(strData)
Return bytes
End Function
'这里可以类推出好几种。
Q2: vb.net 里的substring()有什么作用？应该怎么用？
substring 就是对一个指定的字符窜进行字符窜截取的方法。
运用的形式差不多如下：
截取后的字符窜 = 指定字符窜.substring（开始截取位置[第一位从0开始],截取长度）
Dim str As String = "dsk_cy"
Dim resultStr As String = str.substring(0,2)'截取最左边的两个字符 即 resultStr = “ds”
Dim reulst As String = str.substring(1,2) '截取从最左边数第二位开始的两个字符 即 result = “sk”
Q3: vb.net 字节数组补0
'写入
Dim bytes() As Byte = {34, 23, 43, 43, 55, 3}
Dim items = (From item In bytes Select item.ToString("000")).ToArray()
System.IO.File.WriteAllLines("c:\test.txt", items)
'读取
Dim items2 = System.IO.File.ReadAllLines("c:\test.txt")
Dim bytes2 = (From item In items2 Select Byte.Parse(item)).ToArray()
For Each item In bytes2
Console.WriteLine(item.ToString())
Next
Q4: 用VB怎么在字符串左边加指点数目的0
到底是加左边还是加右边啊？
加左边的话可以用Format(number, "000000")，得到的数如果不足6位则自动在左边补0。
加右边的话，可以用
While Len(st)6
st=st+"0"
Wend
得到的st就保证6位
Q5: VB.NET中如何使string的011 +1 = string的012
Dim a As String = "011"
Dim b As String = "1"
Dim c As String
c = (CInt(a) + CInt(b)).ToString.PadLeft(3, "0")
Label1.Text = c
-----------
将a,b转换为整型之后计算，再转换为string型，之后可以用PadLeft(3, "0")这个来左补零，3表示限定为三位，后面那个“0”就是限定不足3位补0。
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